| Year | Air Quality Level | |||
| I | II | III | IV | |
| 2015 | 83.33 | 16.67 | 0.00 | 0.00 |
| 2016 | 54.55 | 45.45 | 0.00 | 0.00 |
| 2017 | 75.00 | 25.00 | 0.00 | 0.00 |
| 2018 | 62.50 | 37.50 | 0.00 | 0.00 |
| 2019 | 62.22 | 37.78 | 0.00 | 0.00 |